<!DOCTYPE html>
<html lang="zh">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<!--
1. 指数运算符(幂): **
2. Array.prototype.includes(value) : 判断数组中是否包含指定 value
-->
<script type="text/javascript">
  console.log(3 ** 3); // 27
  let arr = [1, 2, 3, 4, 'abc'];
  console.log(arr.includes(2)); // true
  console.log(arr.includes(5)); // false
</script>
</body>
</html>
